Filter material and filter element for air filtration

Abstract

The utility model relates to the technical field of air filtering materials, in particular to a filter material and a filter element for air filtering. The filter material for air filtration comprises a first material layer, a second material layer and a phenolic resin microsphere layer, the first material layer comprises a skeleton cloth layer and a melt-blown cloth layer which are compounded through a hot melt adhesive, and an electrostatic nanofiber layer which is electrostatically spun on the lower surface of the melt-blown cloth layer; the second material layer comprises a PTFE coating film and a non-woven fabric base material layer which are ultrasonically compounded; and a phenolic resin microsphere layer is arranged between the electrostatic nanofiber layer of the first material layer and the PTFE covering film of the second material layer. The filter element comprises a frame part, and the filter material for air filtration is arranged on the frame part. The dust holding capacity of the filter material and the filter element is improved, and the service life of the filter material and the filter element is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of air filtration material technology, and in particular to a filter material and filter element for air filtration. Background Technology

[0002] Dust filtration media are frequently used in daily life (fresh air systems) and industrial production (dust removal devices). These filtration devices typically use multi-layered filter media, consisting of multiple fiber layers and a base fabric firmly bonded together. The media blocks large particles layer by layer. Currently, many manufacturers improve filtration efficiency and dust holding capacity by electretting the fiber layers, but during the dust removal process, a large amount of dust adheres to the media. Over time, the filter pores become clogged, and once the dust holding capacity reaches a certain level, the product becomes unusable. While existing filter media offer some filtration effectiveness, their dust holding capacity is low, they are prone to deformation and failure in humid environments, and it's difficult to balance filtration accuracy and air permeability, resulting in a short lifespan and high replacement rate. Therefore, it is necessary to improve the fiber layer structure to increase the dust holding capacity of the filter media and extend its lifespan. Utility Model Content

[0003] The novel air filtration media and filter element provided by this utility model improve the dust holding capacity of the media and filter element and extend their service life.

[0004] The technical solution adopted by this utility model to solve the technical problem is:

[0005] An air filtration filter media, comprising:

[0006] The first material layer includes a skeleton fabric layer and a meltblown fabric layer bonded together with hot melt adhesive, and an electrostatic nanofiber layer electrospun on the lower surface of the meltblown fabric layer. The pore size of the skeleton fabric layer is 7~9mm, the pore size of the meltblown fabric layer is 8~12μm, and the pore size of the electrostatic nanofiber layer is 4.5~5.5μm.

[0007] The second material layer includes an ultrasonically composited PTFE film and a non-woven fabric substrate layer. The PTFE film has a pore size of 0.8~1.2μm, and the non-woven fabric substrate layer has a pore size of 2.5~3.5μm.

[0008] The slow-flow layer is provided between the electrostatic nanofiber layer of the first material layer and the PTFE film of the second material layer, and the slow-flow layer includes a plurality of dispersed phenolic resin microspheres.

[0009] The edges of the first material layer and the second material layer are bonded together with hot melt adhesive, and the middle part of the first material layer and the second material layer is bonded together with the phenolic resin microsphere layer with hot melt adhesive.

[0010] In the aforementioned air filtration filter material, the skeleton fabric layer is a three-dimensional mesh structure made of interwoven polyester fibers.

[0011] In the aforementioned air filtration filter material, the meltblown fabric layer is a three-dimensional mesh structure formed by interlaced meltblown fibers, and the meltblown fibers are made of polypropylene.

[0012] In the aforementioned air filtration filter material, the electrostatic nanofiber layer is a three-dimensional mesh structure formed by interlacing electrostatic fibers, and the material of the electrostatic fibers is polyester and / or polypropylene.

[0013] In the air filtration media mentioned above, the PTFE membrane is a thin film made of polytetrafluoroethylene material.

[0014] In the above-mentioned air filtration filter material, the plurality of dispersed phenolic resin microspheres are a plurality of regularly arranged phenolic resin microspheres, and the diameter of the phenolic resin microspheres is 1.8mm~2.2mm.

[0015] In the above-mentioned air filtration filter material, the air filtration filter material has a folded structure, the fold width of the fold structure is 2cm to 10cm, and the size of the inner angle formed by the fold structure is 90° to 120°.

[0016] In the above-mentioned air filtration media, 2 to 10 rows of phenolic resin microspheres are arranged longitudinally between two adjacent folds, with at least one phenolic resin microsphere in each row, and the distance between two adjacent phenolic resin microspheres is 3 to 8 mm.

[0017] In the above-mentioned air filtration media, the distance between the phenolic resin microspheres and the crease is at least 10 mm.

[0018] An air filtration filter element includes a frame portion on which the aforementioned air filtration filter material is disposed. The air inlet side of the filter material is a skeleton fabric layer of the first material layer, and the air outlet side of the filter material is a non-woven fabric substrate layer of the second material layer.

[0019] By employing the above technical solution, this utility model has at least the following advantages:

[0020] This invention uses phenolic resin microspheres to add a slow-flow layer to the filter media to facilitate airflow. Smaller particles in the air remain in the slow-flow layer, forming a new filtration layer, thus achieving a secondary filtration effect. This increases the dust holding capacity of the filter media and filter element, and extends their service life.

[0021] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the air filtration filter material proposed in this utility model;

[0023] Figure 2 This is a schematic diagram of the folded structure of the air filtration filter material proposed in this utility model;

[0024] Figure 3 This is a test curve of the dust holding capacity of the air filtration filter material proposed in this utility model. Detailed Implementation

[0025] To further illustrate the technical means and effects adopted by this utility model to achieve its intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of this utility model application is provided in conjunction with the accompanying drawings and preferred embodiments.

[0026] Examples of filter media for air filtration

[0027] like Figures 1-2 As shown, this embodiment provides an air filtration filter material, including a first material layer and a second material layer. The first material layer includes a skeleton fabric layer 1 and a meltblown fabric layer 2 bonded together with hot melt adhesive, and an electrostatic nanofiber layer 3 electrospun on the lower surface of the meltblown fabric layer 2. The pore size of the skeleton fabric layer 1 is 7-9 mm, the pore size of the meltblown fabric layer 2 is 8-12 μm, and the pore size of the electrostatic nanofiber layer 3 is 4.5-5.5 μm. The second material layer includes a PTFE membrane 5 bonded together with ultrasonic waves and a nonwoven fabric layer. The nonwoven fabric substrate layer 6 has a pore size of 0.8~1.2μm and a pore size of 2.5~3.5μm. A flow-retarding layer 4 is provided between the electrostatic nanofiber layer 3 of the first material layer and the PTFE coating 5 of the second material layer. The flow-retarding layer 4 includes a plurality of dispersed phenolic resin microspheres. The edges of the first material layer and the second material layer are bonded together with hot melt adhesive, and the middle part of the first material layer and the second material layer is bonded together with the phenolic resin microspheres with hot melt adhesive.

[0028] This invention creates a buffer layer 4 between the first and second material layers, thus providing a spatial separation between them. Because the pore size of the first material layer is larger than that of the second material layer, dust particles with diameters between 1.2 and 4.5 μm can pass through the first material layer but not the second. These dust particles are dispersed within the buffer layer, causing turbulence in the airflow between the first and second material layers. This prevents the microjet from directly impacting the PTFE membrane layer of the second material layer, thereby reducing filter media consumption and achieving energy savings.

[0029] Because the airflow passing through the first material layer forms a large number of high-speed, discontinuous microjets, the impact of these microjets causes excessively high flow velocities in localized areas of the PTFE membrane 5 surface, creating a "hot spot effect." This overburdens the PTFE membrane 5 in these areas, making it highly susceptible to rapid clogging by particulate matter and forming a dense surface filter cake. Once this filter cake forms on the PTFE membrane 5 surface, the entire air filtration media quickly reaches the set resistance value, rapidly reducing the effective filtration area and severely limiting dust holding capacity and service life. This invention addresses this issue by providing a buffer and expansion area for the microjets through the slow-flow layer. Within this approximately 2mm thick space, the high-speed microjets are sufficiently decelerated, diffused, and mixed, resulting in a more uniform airflow velocity distribution reaching the downstream PTFE membrane 5 surface. This effectively eliminates the "hot spot effect," and the uniform flow field ensures that the entire PTFE membrane 5 filtration area is fully and evenly utilized. Particulate matter is more evenly distributed on the surface and shallow layer of the PTFE membrane 5, significantly delaying the rate at which the set resistance value is reached.

[0030] The skeleton fabric layer 1 in the first material layer is a three-dimensional mesh structure made of interwoven polyester fibers. Specifically, the skeleton fabric layer 1 is prepared using a wet process, which involves mixing short polyester fibers with a slurry, followed by dehydration and drying to form a three-dimensional mesh structure. Specifically, the slurry is a vinyl acetate-acrylic acid copolymer.

[0031] Furthermore, the meltblown fabric layer 2 is a three-dimensional mesh structure formed by interlaced meltblown fibers, and the meltblown fibers are made of polypropylene.

[0032] The second material layer is a PTFE film 5 and a non-woven fabric substrate layer 6 bonded together by ultrasonic welding. Specifically, it is a functional composite material formed by bonding the PTFE film 5 (i.e., polytetrafluoroethylene film) and the non-woven fabric substrate layer 6 together through ultrasonic welding. The second material layer integrates the special physicochemical properties of the PTFE film 5 with the structural support and flexibility of the non-woven fabric. At the same time, it achieves "adhesive-free, efficient, and environmentally friendly" bonding through ultrasonic technology. Ultrasonic bonding uses high-frequency mechanical vibration to generate localized instantaneous high temperatures at the contact surface between the PTFE film 5 and the non-woven fabric substrate layer 6, achieving "fusion" through the thermoplasticity of the materials themselves. In this process, the bonding of the PTFE film 5 and the non-woven fabric substrate layer 6 can be achieved without glue, solvents, or other adhesives.

[0033] Furthermore, the electrostatic nanofiber layer 3 is a three-dimensional mesh structure formed by interlacing electrostatic fibers, and the material of the electrostatic fibers is polyester and / or polypropylene. The diameter of the electrostatic fibers is at the nanometer level; specifically, in this embodiment, the diameter of the electrostatic fibers is 100-200 nanometers.

[0034] Furthermore, the PTFE coating 5 is a thin film made of polytetrafluoroethylene material. The thickness of the film is 0.05 mm.

[0035] Furthermore, the phenolic resin microspheres in the slow-flow layer 4 are regularly arranged phenolic resin microspheres with a diameter of 1.8 mm to 2.2 mm.

[0036] The process of bonding the first material layer and the second material layer with the low-temperature hot melt adhesive is as follows: First, the low-temperature hot melt adhesive is melted, and the phenolic resin microspheres are poured into the melted low-temperature hot melt adhesive so that the surface of the phenolic resin microspheres is uniformly coated with a thin layer of low-temperature hot melt adhesive. Then, the second material layer and the first material layer are simultaneously covered on the phenolic resin microspheres coated with low-temperature hot melt adhesive. After the low-temperature hot melt adhesive cools down, the first material layer and the second material layer are bonded together.

[0037] The diameter of the phenolic resin microspheres coated with low-temperature hot melt adhesive will not change much. Therefore, bonding the first material layer and the second material layer with low-temperature hot melt adhesive will not affect the volume of the gas flow space of the slow-flow layer.

[0038] Furthermore, in order to form a larger surface area for the air filter material and improve the filtration efficiency of the product, the air filter material has a folded structure, the fold width 7 of the folded structure is 2cm to 10cm, and the size of the inner angle formed by the folded structure is 90° to 120°.

[0039] The specific values ​​of the crease width and the size of the inner angle formed by the fold structure can be set according to the requirements of the product (filter element) being prepared.

[0040] Furthermore, the fold 8 of the folded structure of the air filtration filter material is formed by combining the first material and the second material before folding.

[0041] Furthermore, 2 to 10 rows of phenolic resin microspheres are provided between two adjacent folds, with at least one phenolic resin microsphere in each row, and the distance between two adjacent phenolic resin microspheres is 3 to 8 mm.

[0042] The specific number of rows of phenolic resin microspheres can be set according to the requirements of the product (filter element) being prepared.

[0043] Because phenolic resin microspheres have poor plasticity, they are easily crushed and form dust when placed at crease 8. Therefore, the distance between the phenolic resin microspheres and crease 8 should be at least 10 mm, and preferably 30 mm.

[0044] In a specific embodiment with multiple rows of phenolic resin microspheres, the distance between the first and last rows of phenolic resin microspheres and the crease 8 is at least 10 mm.

[0045] The air filtration media has the function of improving filtration efficiency on its own. The two sides of the slow flow layer are respectively composited with an electrospun layer and a PTFE membrane layer 5, which play a primary filtration role on the air flow (the skeleton cloth layer 1, meltblown cloth layer 2 and electrostatic nanofiber layer 3 of the first material layer play a primary filtration role). As the filter media is used for a longer period of time, smaller particles in the air stop flowing in the slow flow layer 4. When the particles in the slow flow layer 4 increase, a new filter layer is formed, which plays a secondary filtration role.

[0046] The air filtration media has a strong dust holding capacity. The product has a multi-layer structure and a slow-flow layer to further increase the dust holding capacity (the test method adopts the dust holding capacity test method in GB / 14295-2019), thereby improving the product's service life.

[0047] like Figure 1 As shown, the electrostatic nanofiber layer 3 of the air filtration filter material prepared in this embodiment is made of polypropylene. The fold width of the fold structure is 5 cm, and the size of the inner angle formed by the fold structure is 90°. Two rows of phenolic resin microspheres are longitudinally arranged between two adjacent folds, with five phenolic resin microspheres in each row, and the distance between two adjacent phenolic resin microspheres is 5 mm. The distance between the two rows of phenolic resin microspheres and the fold is 10 mm.

[0048] The dust holding capacity of an air filter refers to the total mass of standard test dust captured by the air filter when it reaches its final resistance under rated airflow. This utility model, specifically addressing the materials used in this embodiment (i.e....) Figure 1 The dust holding capacity of the materials in this invention was tested according to the method of GB / T 14295-2019. To compare the dust holding effect achieved by the slow-flow layer 4 formed by the phenolic resin microspheres, a comparative test was conducted using filter media without the slow-flow layer 4. The test results of the dust holding capacity are as follows: Figure 3 As shown, under the same resistance conditions, the dust holding capacity per unit area is increased by about 55% when the slow-flow layer 4 is included compared to when the slow-flow layer 4 is not included.

[0049] This invention also includes a comparative test on the filtration efficiency of filter media with and without a flow buffer layer 4 (results are shown in the table below). Specifically, the instrument used was a Longman filter media dust holding capacity testing platform, and the test method followed GB / T14295-2019 standard. Three parallel tests were performed on each sample (samples were of the same size, circular with a diameter of 112.84 mm, and a sample area of ​​100 cm²). 2 After weighing the sample, fix it on the test bench. First, obtain the resistance value before dust collection. Then, use D3 test dust as the test dust and conduct a dust collection test at an air volume of 75L / min. Obtain the resistance in real time. When the resistance reaches the set resistance value of 300Pa, stop the experiment, obtain the test time (in seconds), and weigh the dust after collection.

[0050] The specific measurement results are as follows:

[0051]

[0052] Air filter media with a slow-flow layer reached the set resistance value (300Pa) after 1790 to 1856 seconds in the dust holding test, which is much lower than that of air filter media without a slow-flow layer. Moreover, the dust holding capacity (1.64g to 1.73g) is much higher than that of air filter media without a slow-flow layer (0.85g to 0.88g), and the dust holding capacity per unit area is increased by more than 40%.

[0053] Air filtration cartridge examples

[0054] This embodiment provides an air filtration filter element, which includes a frame portion on which the air filtration filter material of the above embodiment is disposed. The air inlet side of the filter material is the skeleton cloth layer 1 of the first material layer, and the air outlet side of the filter material is the non-woven fabric substrate layer 6 of the second material layer.

[0055] Furthermore, the air filter material is formed by hot pressing, and the edges of the air filter material are fixed together by hot pressing.

[0056] Preferably, the cross-section of the filter element can be of any shape, such as a circular ring, an elliptical ring, a rectangular ring, a rhombus, or other irregular shapes.

[0057] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A filter media for air filtration, characterized in that, include: The first material layer includes a skeleton fabric layer and a meltblown fabric layer bonded together with hot melt adhesive, and an electrostatic nanofiber layer electrospun on the lower surface of the meltblown fabric layer. The pore size of the skeleton fabric layer is 7~9mm, the pore size of the meltblown fabric layer is 8~12μm, and the pore size of the electrostatic nanofiber layer is 4.5~5.5μm. The second material layer includes an ultrasonically composited PTFE film and a non-woven fabric substrate layer. The PTFE film has a pore size of 0.8~1.2μm, and the non-woven fabric substrate layer has a pore size of 2.5~3.5μm. The slow-flow layer is provided between the electrostatic nanofiber layer of the first material layer and the PTFE film of the second material layer, and the slow-flow layer includes a plurality of dispersed phenolic resin microspheres. The edges of the first material layer and the second material layer are bonded together with hot melt adhesive, and the middle part of the first material layer and the second material layer is bonded together with the phenolic resin microspheres with hot melt adhesive.

2. The air filtration media according to claim 1, characterized in that, The skeleton fabric layer is a three-dimensional mesh structure made of interwoven polyester fibers.

3. The air filtration media according to claim 1, characterized in that, The meltblown fabric layer is a three-dimensional mesh structure made of interwoven meltblown fibers, and the meltblown fibers are made of polypropylene.

4. The air filtration media according to claim 1, characterized in that, The electrostatic nanofiber layer is a three-dimensional network structure formed by interlacing electrostatic fibers, and the electrostatic fibers are made of polyester and / or polypropylene.

5. The air filtration media according to claim 1, characterized in that, The PTFE coating is a thin film made of polytetrafluoroethylene material.

6. The air filtration media according to claim 1, characterized in that, The plurality of dispersed phenolic resin microspheres are arranged in a regular pattern, and the diameter of the phenolic resin microspheres is 1.8 mm to 2.2 mm.

7. The air filtration media according to claim 1, characterized in that, The air filtration media has a folded structure, the fold width of which is 2cm to 10cm, and the size of the inner angle formed by the fold structure is 90° to 120°.

8. The air filtration media according to claim 7, characterized in that, There are 2 to 10 rows of phenolic resin microspheres arranged longitudinally between two adjacent creases, with at least one phenolic resin microsphere in each row, and the distance between two adjacent phenolic resin microspheres is 3 to 8 mm.

9. The air filtration media according to claim 7, characterized in that, The distance between the phenolic resin microspheres and the crease is at least 10 mm.

10. An air filtration filter element, characterized in that, The filter element includes a frame portion, on which an air filtration filter material according to any one of claims 1 to 9 is provided. The air inlet side of the filter material is the skeleton fabric layer of the first material layer, and the air outlet side of the filter material is the non-woven fabric substrate layer of the second material layer.

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